Από τη μία είναι εύρημα, από την άλλη απομίμηση.

It is a very common Greek contrast pattern, equivalent to on the one hand ... on the other hand ....

So here the speaker is setting up two opposite or competing ways of looking at the same thing.

You will also hear longer versions such as:

• Από τη μία μεριά ..., από την άλλη μεριά ...
• Από τη μια ..., από την άλλη ...

All of these are very natural.

This is about the feminine accusative singular article την.

In Modern Greek, the final -ν of την is often dropped before certain consonants, but kept before vowels and some consonants.

• τη μία because μία starts with μ
• την άλλη because άλλη starts with a vowel, α

So both forms come from the same article:

• την μία → commonly written τη μία
• την άλλη stays την άλλη

This is completely normal spelling and pronunciation.

They are in the accusative because they follow the preposition από.

In Modern Greek, από takes the accusative:

• από τη μία
• από την άλλη

Even though English uses from, Greek does not switch to a genitive here. With από, accusative is the standard pattern.

They are feminine because the expression is short for something like:

• από τη μία πλευρά
• από την άλλη πλευρά

That is, from the one side / from the other side.

The noun πλευρά is feminine, so the words that go with it are feminine too. In the actual sentence, πλευρά is omitted because the shorter idiom is so common.

Originally, yes, it is related to one, but in this expression it functions more like the one in the pair the one ... the other.

So in από τη μία ..., από την άλλη ..., you should learn it as part of a fixed contrast expression, not as a simple counting word.

Also note that Greek often writes this as either:

• μία
• μια

Both are common. μία is a bit more explicit in writing, while μια is very common in everyday Greek.

Greek often leaves out a repeated verb when the meaning is obvious from the parallel structure.

So:

• Από τη μία είναι εύρημα, από την άλλη απομίμηση.

is understood as:

• Από τη μία είναι εύρημα, από την άλλη είναι απομίμηση.

This omission is very natural in Greek, especially in balanced contrasts like this one.

Because after είναι, Greek very often uses a noun without an article when it is classifying or describing something.

So:

• είναι εύρημα
• είναι απομίμηση

works like saying:

• it is a find
• it is an imitation

Greek does not always need an equivalent of English a/an here.

If you added articles:

• είναι ένα εύρημα
• είναι μια απομίμηση

that is also possible, but it can sound a little more specific or a little less compact. The article-less version is very natural in this kind of statement.

• εύρημα is neuter
• απομίμηση is feminine

That matters if you later add adjectives or pronouns.

For example:

• ενδιαφέρον εύρημα = interesting find
• καλή απομίμηση = good imitation

So even though both nouns appear in the same sentence, they belong to different gender classes.

Yes. μια and μία are both used in Modern Greek.

In this sentence, these are both natural:

• Από τη μία είναι εύρημα, από την άλλη απομίμηση.
• Από τη μια είναι εύρημα, από την άλλη απομίμηση.

The version with μία is a little more careful or traditional in writing, while μια is extremely common in everyday use.

The exact wording can vary, but the pattern itself is very stable.

The most natural structure is:

• Από τη μία ..., από την άλλη ...

You could also say the fuller version:

• Από τη μία είναι εύρημα, από την άλλη είναι απομίμηση.

Greek does have flexible word order, but in this kind of contrast, the given order sounds very natural and idiomatic. If you move things around too much, it may sound less smooth or less balanced.

It is neutral and natural. The contrast pattern Από τη μία ..., από την άλλη ... works in both speech and writing.

A few style notes:

• Από τη μια / από τη μία is very common in everyday language.
• Από τη μία μεριά / από την άλλη μεριά sounds a bit fuller and more conversational.
• The shorter version in your sentence is concise and perfectly standard.

So this is a good pattern to learn and reuse in many situations.